Self-locking, self-actuating, light-weight folding strut



1968 w. w. VYVYAN ETAL 3,408,029

SELF-LOCKING, SELP-ACTUATING, LIGHTWEIGHT FOLDING STRUT Filed Ocx. 10, 1966 2 Sheets-Shee 1 I. /2o 24 L22 l 1 MIMI! .munmum" J Fig.2

if 22 20 I I4 :24

H2 .nlllllllllli' ,muuummLi INVENTORS WESLEY W. VYVYAN LAURENCE H. WARDEN Fig. 6 BY Oct. 29, 1968 w. w. VYVYAN ETAL 3,408,029

SELF-LOCKING, SELF-ACTUATING, LIGHTWEIGHT FOLDING STRUT Filed Oct. 10, 1966 2 Sheets-Sheet 2 46 46 W 4e 46 M l T- .1 4o i g 40 38 40 i E g g 38 36 E E 38 E Z g 9 Fig. 8

INVENTORS WESLEY W. VYVYAN LAURENCE H. WARDEN Y mam United States Patent 3,408,029 SELF-LOCKING, SELF-ACTUATING, LIGHT- WEIGHT FOLDING STRUT Wesley W. Vyvyan and Laurence H. Warden, San Diego,

Calif assignors to The Ryan Aeronautical Co., San

Diego, Calif.

Filed Oct. 10, 1966, Ser. No. 585,597 6 Claims. (Cl. 248-351) ABSTRACT OF THE DISCLOSURE The strut is made from resilient sheet material preformed with a curved cross section of arcuate or tubular configuration, and has hinge means at the ends for attachment to structural members to be opened or separated from a closed position. To fold the strut the sheet material is merely flattened at the point of bend, the tubular form being unrolled and opened flat, allowing the strut to bend easily. When released the strut will straighten itself and snap back to the curved, rigidly locked configuration.

The present invention relates to supports and braces and specifically to a self-locking, self actuating, lightweight folding strut for extension and support of a pair of interconnected members.

A conventional type foldable strut or brace connecting relatively movable structural members requires a hinge at each end connection with the associated member and a further hinge intermediate the ends. If the strut is to be self-extending to open or separate the structural members, or to assist in such an action as in raising a lid, at least one of the hinges must incorporate some type of spring means. For some uses, particularly in space vehicles, such a structure is unnecessarily heavy and is subject to binding.

The strut described herein is hinged only at its ends and is made from resilient material formed to provide an inherent rigidity when extended, yet being readily folded by an intentional local deformation. When the folded strut is released its own resiliency will cause the strut to open and lock into its fully extended position without assistance. The strut can be used to connect members which are hinged together, so that the strut spreads the members apart and forms a diagonal brace or multiple struts can interconnect distinct members which are to be separated into parallel or some other spaced relation. In the latter instance stops are incorporated into the strut hinges, but these are only for alignment of the structural members and are not necessary to the rigidity of the struts.

Two forms of the strut and typical uses are illustrated in the drawings, in which:

FIGURE 1 is a side elevation view of the basic form of the strut in folded position between a pair of hinged members;

FIGURE 2 is a side elevation view of the structure with the strut extended;

FIGURE 3 is an enlarged sectional view taken on line 33 of FIGURE 2;

FIGURE 4 is a view similar to FIGURE 1, but showing an alternate strut suitable for lighter loads;

FIGURE 5 is a side elevation view of the structure of FIGURE 4 with the strut extended;

FIGURE 6 is an enlarged sectional view taken on line 6-6 of FIGURE 4;

FIGURE 7 is a side elevation view of a pair of parallel members interconnected by a pair of struts in folded position;

3,408,029 Patented Oct. 29, 1968 FIGURE 8 is a side elevation view of the structure of FIGURE 7 with the struts extended; and

FIGURE 9 is an enlarged view taken on line 9-9 of FIGURE 8.

Similar characters of reference indicate similar or identical elements and portions throughout the specification and throughout the views of the drawing.

The basic strut 10, shown in FIGURES 1-3, is of rolled tubular form with one longitudinal edge portion 12 overlapping the other, but not secured thereto. The strut is made from metal, plastic, or composite material capable of being flattened out and folded without retaining any deformation and which has sufficient resiliency to spring back to its preformed configuration when released. Fixed to each end of strut 10 is a hinge fitting 14 having a hinge pin 16, the two hinge pins being parallel to each other and perpendicular to the longitudinal axis of the strut.

The two structural members 18 and 20 are interconnected by a hinge 22 and may be frame or beam elements, panels, or other such structures. As a particular example, one could be a panel or similar element hinged on a basic frame, such as a solar cell panel or antenna on a space vehicle.

On each member 18 and 20, at an appropriate distance from hinge 22, is a hinge bracket 24. The hinge brackets are positioned so that the strut, when attached to the brackets by hinge pins 16, will extend rigidly when the members 18 and 20 are disposed at the required angular relationship. For large structures several struts may be used at suitable spaced positions to act in unison.

To fold the strut 10, the overlapped portion 12 is lifted at the center of the strut and the inner edge portion 26 is grasped. When the two edges are pulled apart the material will be flattened out and can then be folded, allowing members 18 and 20 to be swung together with the strut folded double between the members. Any suitable means of restraint, not shown, may be used to hold the structure in folded position. When restraint is removed, the natural resiliency of the strut material will extend the folded portion 28 until the strut can snap back to its tubular form and become rigid.

As illustrated, the overlapped portion 12 extends about degrees around the tube, which will provide a high degree of rigidity yet still make it practical-to fold the strut. Varying degrees of overlap may be used, or no overlap at all depending on the rigidity and self-erecting force required.

For lighter loads, in fact, the strut 30, shown in FIGURES 4-6, may be used. This strut is merely a trough-like element, concave or cambered in cross section to provide the required rigidity and resistance to bending or compression loads, all other structures and fittings being as described above. Folding is accomplished by flattening the central portion of the strut in the same manner but with less effort than the tubular strut. The stored energy available for extending the strut by its own resiliency will be less than that of a complete tube, but will be ample for many uses.

In addition to its use as a diagonal brace between hinged members, the strut can be used in multiple to separate and hold parallel or other spaced members. A parallel arrangement is shown in FIGURES 7-9, in which structural members 32 and 34 are connected by a pair of spaced struts 3'6, which may be of tubular or cambered cross'section type. Each strut has hinge fittings 38 at the ends, which are connected by hinge pins 40 to hinge brackets 42 on the members 32 and 34. The hinge fittings 38 have projecting stops 44 orthogonal to the hinge pins and to the longitudinal axis of each strut. Hinge brackets 42 have stop faces 46 against whichthe stops 44 bear when the struts are fully extended, or alternatively, adjacent portions of the structural members themselves can act as stop faces. With the orthogonal stops and struts of ,equal length, the members are held in parallel relation with the struts perpendicular therebetween.

By suitable angular dispositionof stops 44 the extended struts can .be inclined to the members if necessary. Further, by use of struts of different lengthsthe members can be held at any required angular relation when separated.

Several structural members or assemblies may be interconnected to open into a stacked array, or combined with hinged members to form a complex structure which is entirely self-erecting from .a compact stored configuration. Such structures are particularly applicable to space vehicles, where compactness is desirable during launch and light weight and reliability of operation are essential. It will be evident that associated structure, such as flexible or foldable panels, could be secured to the various structural members, to be extended and supported by the struts. Many other uses will be apparent, such as for quick acting doors, screens, lids and the like.

It is understood that minor variation from the form of the invention disclosed herein may be made without departure from the spirit and scope of the invention, and that the specification and drawings are to be considered as merely illustrative rather than limiting. 1

We claim:

1. Self-locking, self-actuating foldable strut means for connection between structural members to be spread apart, the strut means including at least one strut comprising:

an elongated element having a preformed unidirectionally curved cross section and beingof-resilient sheet material capable of returning to its preformed configuration from a deformed, folded condition with the sheet material flattened at the fold; the ends of said elongated'element having hinge fittings for-pivotal connection to the structural-members. 2. he -str nctur eiacc"ordingjto claim '1, wherein said elqfigatea 1 s ris ';.ubsta ntially, tubular in, cross section with longitudinally coext'en'sive,"separable ge portions. 3. The structure accordingto claim;1 wherei'n said elongated element .is .of;rolled tubular form with one longitudinal edge portion overlapping the other.

4. The structure according to claim 1 and including hinge means whereby the .st'ructural membe'rs' are hinged together, and said. elongated. element, when extended, is disposed diagonally between the members;

5. flfhe structure according to claimjl, wherein said strut means includes a plurality of stints in spaced relation, wherebysaid struts, in extended position, support the structural members, in the plane through said struts, in an angular,.,relat ionship, including parallelism, determinedby the relative lengths of said struts. I 6.; The structure according. to claim 5, and including i stop means integral with said hinge fittings and being engaged when said strutsare extended to hold the members in predetermined alignment relative to the struts.

References Cited UNITED STATES PATENTS 2,673,760 '3/1954 Hawks 16'85 X 3,295,556 1/1967 Gertsma et al. 138 119 ROY D. FRAZIER,'Primary Examiner. F. DOMOTQR, Assistant Examiner. 

